1. Field of the Invention
The present invention relates to a digital camera, and more particularly to a digital camera having an image sensor which may be cleaned by the user.
2. Description of the Related Art
A conventional digital camera may have a detachable lens. A subject image entering through the lens is directed to an optical finder through a return mirror. The user finds the subject image through the optical finder. When the user pushes a shutter release button, the return mirror is raised, a shutter curtain runs, and light from the subject arrives at an image sensor. The images sensor produces the subject image as an electrical signal, and outputs it as image data. The image data is processed and stored on a recording medium as an image file. The image sensor has a front surface which faces a photographic subject. A low-pass filter is attached onto the front surface of the image sensor. Hereinafter, it will be assumed that the image sensor has a low-pass filter attached to its front surface.
The image sensor is provided in a mirror box of a digital camera with movable elements such as a shutter curtain and a return mirror. These movable elements move with the taking of every photograph, and graze the supports of the movable elements, creating dust particles between the supports and the movable elements. Additionally, in the case of a digital camera having a detachable lens, dust particles may enter the mirror box when the lens is removed. These dust particles may become attached to the image sensor and block light arriving at the imaging sensor. Therefore, the dust particles may reduce quality of a photographed image.
To resolve this problem, Japanese Unexamined Patent Publication (KOKAI) No. 2005-341381 discloses that pixels having low output value in an image signal are detected, and the data for those pixels is corrected because dust particles are assumed to be attached at those pixel locations.
However, according to conventional constructions, pixel data may be uncorrectable if the number or size of the dust particles attached to the image sensor is large. Thus, the attached dust particles degrade the photographed image.